Biofouling Growth in Cold Estuarine Waters and Evaluation of Some Chitosan and Copper Anti-Fouling Paints

Ecological concerns about antifouling paints containing non-green tin and copper compounds have highlighted the need for environmentally friendly alternatives. We report here a field test conducted in estuarine waters over two months designed to evaluate the efficiency of a number of active natural and man-made chemical ingredients added into a silicon-polyurethane marine paint. Early steps of biofouling in cold seawater of the St. Lawrence Estuary (Canada) were observed. Analyses, including dry biomass, flow cytometry and spectrofluorimetry, demonstrated a short-term antibacterial action of chitosan-based paints although no significant anti-algal action was observed. Cuprous oxide paints were efficient against bacteria and algae invasion in the first two weeks, especially those with added organic biocides such as isothiazolone and copper pyrithione. However, the overall dry biomass and chlorophyll a content were similar for all chitosan-and copper-based paints after 63 days. Microscopic observations revealed variation in the highly diverse benthic diatom population including species Navicula, Melosira, Cocconeis, Nitshzcia, Fragilaria and Amphora. Results suggest no real long-term efficiency for tested antifouling paints and highlight a particular need for green antifouling ingredients that are active under northern estuarine conditions

Utilisation de polymères de chitosane dans la formulation de peintures marines anti-salissures

Les conséquences environnementales découlant de l'utilisation de peintures antisalissures à base de métaux lourds ont mis en évidence l'urgence de développer de nouvelles alternatives sécuritaires pour le milieu marin. Des composés écologiques capables de restreindre la croissance des salissures, et particulièrement des premiers stades bactériens et algaux, sont recherchés. Polymère abondant et dérivé de résidus de crevettes, le chitosane possède des propriétés antibactériennes et antialgales bien connues qui pourraient s'avérer utiles en tant qu'ingrédient bioactif dans une peinture anti-salissure. Des polymères de chitosanes, variant en poids moléculaire et en degré de désacétylation, ont été ajoutés à une peinture marine commerciale au polyuréthane et à la silicone, Easypoxy. Leur efficacité a été comparée avec des peintures anti-salissures existantes dans un test d'immersion statique effectué dans des eaux nordiques et salées. Les résultats, obtenus suite à des analyses biologiques et chimiques détaillées des premiers moments de la colonisation, démontrent une activité antibactérienne du chitosane. Cependant, les peintures au chitosane, tout comme les peintures sans additif Easypoxy, n'ont démontré aucune action anti-algale. De plus, les observations microscopiques révèlent une plus grande diversité de diatomées à la surface des peintures au chitosane et de la peinture Easypoxy qu'à la surface des peintures à base de cuivre, indiquant une action anti-algale réelle et ciblée de l'oxyde de cuivre. Bien qu 'une efficacité antisalissures, autant antibactérienne qu'antialgale, des peintures à base d'oxyde de cuivre, Bottomkote XXX, soit observée, et particulièrement celles auxquelles les biocides organiques Sea-Nine 211 et Copper Omadine sont ajoutés, le poids total de matière organique récolté à la surface des plaquettes n'est pas significativement différent d'une peinture à l'autre, même après 63 jours d'immersion. À long terme, l'emploi du cuivre et de biocides n'apparaît pas être avantageux. La biomasse totale mesurée à la surface d' Easypoxy semble toutefois présenter des valeurs supérieures aux autres. Toutes les méthodes utilisées ont bien sûr permis de comparer l'efficacité des différentes peintures testées, mais aussi de suivre de façon précise et détaillée la progression de la colonisation par les salissures marines dans les premiers temps d'immersion des structures marines dans les eaux froides du Saint-Laurent. De plus, les résultats obtenus démontrent bien que l'utilisation du chitosane en tant qu 'agent anti-bactérien combiné à un composé anti-algal écologique pourrait s'avérer une perspective de développement de peintures mannes sécuritaires pour l'environnement

Evidence of Anti-Proliferative Activities in Blue Mussel (Mytilus edulis) By-Products

Shellfish waste components contain significant levels of high quality protein and are therefore a potential source for biofunctional high-value peptides. The feasibility of applying a pilot scale enzymatic hydrolysis process to whole Mytilus edulis and, by fractionation, recover hydrolysates presenting a biological activity of interest, was evaluated. Fractions were tested on four immortalized cancerous cell lines: A549, BT549, HCT15 and PC3. The 50 kDa fraction, enriched in peptides, presented anti-proliferative activity with all cell lines and results suggest a bioactive molecule synergy within the fraction. At a protein concentration of 44 µg/mL, the 50 kDa fraction induced a mortality of 90% for PC3, 89% for A549, 85% for HCT15 and of 81% for BT549 cell lines. At the low protein concentration of only 11 µg/mL the 50 kDa fraction still entails a cell mortality of 76% for A549 and 87% for PC3 cell lines. The 50 kDa fraction contains 56% of proteins, 3% of lipids and 6% of minerals on a dry weight basis and the lowest levels detected of taurine and methionine and highest levels of threonine, proline and glycine amino acids. The enzymatic hydrolysis process suggests that Mytilus edulis by-products should be viewed as high-valued products with strong potential as anti-proliferative agent and promising active ingredients in functional foods

Evidence of Anti-Proliferative Activities in Blue Mussel (Mytilus edulis) By-Products

Shellfish waste components contain significant levels of high quality protein and are therefore a potential source for biofunctional high-value peptides. The feasibility of applying a pilot scale enzymatic hydrolysis process to whole Mytilus edulis and, by fractionation, recover hydrolysates presenting a biological activity of interest, was evaluated. Fractions were tested on four immortalized cancerous cell lines: A549, BT549, HCT15 and PC3. The 50 kDa fraction, enriched in peptides, presented anti-proliferative activity with all cell lines and results suggest a bioactive molecule synergy within the fraction. At a protein concentration of 44 µg/mL, the 50 kDa fraction induced a mortality of 90% for PC3, 89% for A549, 85% for HCT15 and of 81% for BT549 cell lines. At the low protein concentration of only 11 µg/mL the 50 kDa fraction still entails a cell mortality of 76% for A549 and 87% for PC3 cell lines. The 50 kDa fraction contains 56% of proteins, 3% of lipids and 6% of minerals on a dry weight basis and the lowest levels detected of taurine and methionine and highest levels of threonine, proline and glycine amino acids. The enzymatic hydrolysis process suggests that Mytilus edulis by-products should be viewed as high-valued products with strong potential as anti-proliferative agent and promising active ingredients in functional foods

Bioassay-guided fractionation approach for determination of protein precursors of proteolytic bioactive metabolites from macroalgae

International audienceIn the last decades, an upsurge in the occurrence of chronic diseases caused by hypertension and oxidative stress has been observed. The objective of this research was to isolate and characterize groups of antioxidant and anti-hypertensive natural bioactive peptides originating from hydrolyzed proteins of the red seaweeds Solieria chordalis and Palmaria palmata, the green seaweed Ulva lactuca and the brown seaweed Saccharina longicruris. Enzymatic hydrolysis by trypsin and chymotrypsin was performed in order to release bioactive algal peptides. Three antioxidant assays, 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC), were used to determine the activity of seaweed peptides. Angiotensin-converting enzyme (ACE) inhibition assay was used to evaluate the anti-hypertensive potential. Additionally, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses and database searches allowed for protein identification, indicating where these bioactive peptides originated from. Fractions of red seaweeds, especially S. chordalis, produced by chymotrypsin and trypsin hydrolysis, exhibited higher in vitro antioxidant and ACE inhibitory activities than the parent proteins. Size exclusion chromatography highlighted two groups of bioactive peptides: (i) peptides with molecular weight (MW) between 1,400 and 3,200 Da displaying antioxidant activities and (ii) smaller peptides (MW <1,000 Da) displaying both antioxidant and ACE inhibitory activities. LC-MS/MS analyses of the antioxidant subfractions of P. palmata and S. chordalis were performed, and several peptide sequences were elucidated, using tandem mass spectrometry. Of all identified peptides of S. chordalis, 61 and 43 % came from the hydrolysis of ribulose-1, 5-biphosphate carboxylase/oxygenase (RuBiSCo) enzymes. Phycoerythrin, elongation factors, photosystems and cytochrome oxidase clusters represented between 3 and 14 % of identified peptides in S. chordalis fractions. This is the first time, to the author’s knowledge, that distinction between several groups of bioactive peptides, within seaweed protein hydrolysates, has been reported. In addition, proteins of origin were also identified